Rotary pump assembly



p 1953 J. B. PARSONS 2,650,544

ROTARY PUMP ASSEMBLY Filed May 17, 1949 FIE-.1.

/2 2 U '/3 y la 1 s -Z/ v5 INVENTOR.

(lo/7n 5. Parsons /1101M a. fill/L ATTORNEY Patented Sept. 1, 1953 UNITED STATES PATENT OFFICE ROTARY PUMP ASSEMBLY John B. Parsons, Maumee, Ohio Application May 17, 1949, Serial No. 93,780

1 Claim. 1

This invention relates to pumps of the type having two rotor members, one disposed within and eccentric to the other, the outer rotor having internal teeth and the inner rotor having external teeth, the contours on each outlined by the tooth form of the other at regular angular motion, and an object is to improve the construction of pumps of this character so that the power necessary to drive the rotors is substantially reduced.

Another object is to produce a pump of the above character in which the outer rotor is sealed by a plate which when in operation, is held in sealing contact by fluid pressure, the inner rotor being out of engagement with the late, a reduced bearing surface being provided between the opposite face of the outer rotor and the adjacent housing end wall, thereby to reduce the frictional contact area as much as possible.

Other objects and advantages of the invention will hereinafter appear, and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawings, in which Figure 1 is a fragmentary elevation of a pump assembly, portions being broken away to show the pump structure in section;

Figure 2 is a transverse sectional view substantially on the line 2-2 of Figure 1; and

Figure 3 is a sectional view substantially on the line 33 of Figure l.

The illustrated embodiment of the invention comprises a casing I in which is disposed a pump housing H, the outer end of which is open and the inner end of which is formed with a wall l2 which has laterally spaced inlet port l3 and outlet port [4, the inlet port I3 communicating through a passage [5 to a suitable liquid reservoir (not shown) and the outlet port I4 communicating with a passage [6 leading to the work. Super- ;posed on the casing I0 is an electric motor 11 which has an armature shaft [8 depending therefrom with the lower end portion extending into :the interior of the pump housing i3.

Secured to the lower end portion of the armature shaft H! by a key [9 is an inner rotor member 20 which has external teeth adapted progres- The outer rotor member 2| rotor member 20. The inner rotor member 20 is mounted eccentrically with respect to the outer .rotor member 2i and moves the same ahead of it progressively and continuously forming suction and compression phases which are timed with respect to the inlet and outlet ports l3 and I4 respectively, thus to provide a substantially continuous flow of fluid under pressure from the pump. The rotors are provided with contours, such that the teeth, in theory, wipe or make continuous travelling contact over those of the other during rotation. The above described pump is old in the art and it is believed that this brief description is deemed adequate for a full understanding of the invention.

The outer end of the pump housing ll 1 is closed by a rigid plate or disc 22 secured in place by a plurality of screws 23. Formed on the outer face of the outer rotor member 2i is an annular recess or socket 24 into which snugly fits a metallic disc 25 which is relatively rigid and which is normally held seated within the socket by a spider-like spring 26 which has a plurality of arms bearing against the under side of the plate 25 and has an outwardly projecting nubbin-like portion 21 which bears against the inner face of the closure plate 22.

It will be noted that the inner rotor member 20 is of less depth than the depth of the outer rotor member 2| so that the outer face of the inner rotor member 20 is spaced from the inner face of the disc 25.

In order to reduce the bearing contact between the inner face of the outer rotor member 2| and the end wall 12 of the housing H, the adjacent edge portion of the outer rotor member is chamfered, as indicated at 28. By providing the chamfered area 28, only a relatively small surface of the outer rotor member 2| is in bearing contact with the end wall [2 of the housing.

In operation, it will be understood that the fluid, such as liquid under pressure, finds its way to the outer face of the disc 25, inasmuch as the running fit between the outer rotor 2| and the housing I2 is not liquid-tight, and exerts inward pressure on the outer rotor member 2!, urging it against the end wall l2, but since the bearing contact between these members is reduced to a minimum, the frictional loss is reduced substantially. Inasmuch as the inner rotor member 20 is spaced from the disc 25, the friction which would otherwise be imposed upon the inner rotor member is eliminated and although the pumping efficiency is slightly reduced, this is more than compensated for by the reduction in power necessary to drive the pump. Empirically it is found that as much as thirty percent reduction in power necessary to drive the pump is thereby achieved.

3 It is to be understood that numerous changes in details of construction, arrangement and operation may be efiected Without departing from the spirit of the invention especially as defined in the appended claim.

What I claim is:

A pump comprising a housing having a cylindrical cavity open at the outer end, a pair of mating toothed pump rotor members arranged one within the other and disposed Within said cavity, a drive 'for the inner rotor member, said housing having spaced inlet and outlet ports at the inner .side of said rotor members, a closure for the outer end of said cavity, the inner rotor member men-1g of appreciably less depth than the outer rotor member so that the outer end of the inner rotor member is spaced from the adjacent end of the the outer fa'ce-of said disc and having a central nubbin-llkeportion bearing against the inner-face of said closure, whereby pressure against the 4 outer surface of the plate forces the same against the outer rotor only so as to enable rotation of the inner rotor without frictional contact with such plate.

JOHN B. PARSONS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 947,679 Nielsen Jan. 25, 1910 1,486,837 Hill Mar. 11, 1924 1,590,384 Kucher June 29, 1926\ 1,694,805 Wiltse Dec 11, 1928 1309.580 Jensen Apr. 16, 1929 1,879,136 Dubrovin Sept. 27, 1932 1,970,146 Hill Aug. 14, 1934 2,243,872 Lysholm June 3, 1941 2,324 ,903 Beckman July 20, 1943 2,383,153 Parsons Aug. 21, 1945 2,389,728 Hill l Nov. 27, 1945 2,495,061 Shaw a July 30, 1946 2, i28,-18l Sibley Sept. 30, 1947 2,434,135 Witc'hger Jan. 6, 1948 FQREIGN PATENTS Number Country Date 145,501 i reatrBritain Jan. 20, 1921 

